X-ray magnetic circular dichroism XMCD measurements were performed at the U M4,5 edges for U/ Fe,
U/Co, U/ Ni, and U/Gd multilayers. In the case of the U/Fe system, a significant polarization of the U 5f
electrons was found, but not for U/Co or U/Ni multilayers. We ascribe this to a hybridization of U 5f and
Fe 3d states, which overlap in energy near the Fermi level. In the U/Gd system, the XMCD signals were small
and yielded magnetic moments of order 0.02B. The spatial extent of the U 5f polarization is different from
that of the U/Fe system and is oscillatory, extending into the center of the U layers.